Electric-arc lamp.



No. 768,745. PATENTED AUG. 30, 1904. MLP. GOODRIGH. ELECTRIC ARG'LAMP.

APPLICATION FILED AUG.13. 1903.

N0 MODEL.

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MELVILLE F. GOODRICH, OF NEXVTON, MASSACHUSETTS.

ELECTRIC-ARC LAMP.

SPECIFICATION forming part of Letters Patent No. 768,745, dated A g 30, 1904. Application filed August 13,1908. Serial No. 169,362. (No model.)

To all whont it ntcty concern.-

Be it known that I, MELVILLE F. GooDRroH, of Newton, in the county of Middlesex and State of Massachusetts, have invented certain new and useful Improvements in Electric-Arc Lamps, of which the following is a specification. 7

This invention relates to electric-arc lamps; and its object is to enable the movable carbon or electrode to feed on a smaller variation of current than is permissible with the usual types of lamp.

In many lamps as at present constructed there is a retarding device, such as a dash-pot, for preventing overthrow or sudden movements of the movable carbon, and as these lamps are now constructed it is common to impose the influence of the dash-pot or retarding device upon the movable carbon in every upward or retracting movement of said carbon. The result is that a considerable variation of current is required to efiect the feed of the carbon.

According to my invention I employ a lostmotion device whereby the dash-pot or other retarder is at first imposed upon the movable electrode in striking the are, but is afterward automatically disconnected through a sufficient range of movement of the movable electrode to permit the regulating and feeding movements of the latter independently of the retarder, thus permitting the lamp to regulate on a small variation in current. In practice I have found that, whereas in the ordinary alternating-current lamp there is a variation of some two amperes of current through the lamp, when my improved construction is employed the variation is only about threetenths of an ampere.

The invention is applicable to both alternating and direct current lamps.

The accompanying drawing represents a side elevation, partly in section, of portions of an electric-arc lamp, showing the application of my improvement.

1n the drawing, 10 is the movable carbon or electrode. 11 is the fixed carbon tube or guide. 12 is the controlling and regulating solenoid; 18, the armature thereof; 14., the carbon-engaging clutch, and 15 a vertical bar or link connecting the solenoid-armature with the clutch, there being at 16 the usual arrangement whereby the armature in rising yieldingly carries with it the bar 15.

At 17 on the tube 11 is pivoted a lever 18, having one arm connected by a link 19 with the piston 20 of a retarding dash-pot 21. the other arm of said lever having a counterbalancing-weight 22 adjustable along the lever by means of a pin 23 and a series of holes 24.

A lost-motion connection is etfected between the lever 18 and bar 15 by means of a pin 26 on the lever 18, which works in a short vertical slot 27 in the bar 15. There is also a lug 28 clamped to the bar 15, so as to be adjustable in height therealong and adapted to rest in a notch 29 on the weighted arm of lever 18 when no current is passing through the lamp.

The operation is as follows: Before the arc is struck the parts have the positions represented in the drawing, with the clutch 1d at its lower releasing-stop, the pin 26 in the bottom of the slot 27, and the lug 28 resting in the notch 29. V hen the current is turned on, the suction of the solenoid 12 causes the armature 13 and bar 15 to rise, and this motion is communicated to the movable carbon 10 through the clutch 1 1 and to the lever 18 through the pin 26 and the bottom of the slot 27. Thus the retarding effect of the dash-pot 21 is at first imposed on the carbon 10, and the latter draws away slowly from the lower carbon in establishing the arc. hen the are is established and the carbon burns away, the current through the solenoid 12 decreases and the armature 13, bar 15, clutch 14c, and carbon 10 start to descend. Since the dash-pot piston 20 and connected parts are counterbalanced by the weight 22 on the lever 18, these parts remain in the highest position to which they were moved by the ascent of the bar 15, and the bar and its connected parts are allowed to descend independently of the influence of the dash-pot piston within limits imposed by the pin 26 and slot 27. The said slot is of such a length that the ordinary feeding movements of the carbon 10 can take place without any movement of the dash-pot piston 20, so that whenever said carbon is retracted during these feeding movements only a small amount of current is required to retract it and the variation of current through the lamp during its regulating movements is much reduced. WVhen the current is turned off from the lamp, the parts reassume the positions shown in the drawing, and in doing so the lug 28 enters the notch 29 and engages lever 18, oscillating the latter to its initial position and carrying the piston 20 upwardly in the dash-pot 21, ready to exert its retarding action when the arc is again struck.

It will be seen that the function of the counterbalance for dash-pot piston 20 is to permit the piston and counterbalancing-lever to remain in difierent positions without support, so that the magnet armature and clutch may perform their regulating movements in both directions untrammeled by the dash-pot.

The invention of course is not confined to the details of construction herein set forth.

I claim 1. In an electric-arc lamp, the combination of electrodes, one of which is movable, an electromagnet having a clutch controlling the feed of the movable electrode, a retarder having a movable member connected to retard said clutch on the initial electrode separating movement thereof, and means for automatically permitting a limited free movement of said clutch in both directions independently of the movable member of the retarder throughout the normal regulating action of the clutch.

2. In an electric-arc lamp, the combination of electrodes, one of which is movable, an electromagn et having a clutch controlling the feed of the movable electrode, a retarder having a movable member and counterbalance therefor capable of remaining in different positions without support, and a lost-motion connection between said clutch and the movable member of the retarder.

3. In an electric-arc lamp, the combination of an electrode-engaging clutch, a controlling electromagnet, a dash-pot, a weighted lever counterbalancing the movable member of said dash-pot, mechanism exclusive of the lever connecting the magnet armature and the clutch, and a lost-motion connection between said mechanism and the lever.

4. In an electric-arc lamp, the combination of an electrode-engaging clutch, a controlling electromagnet, a retarding device, and connections between said parts including a lostmotion device permitting normal regulating movements of the clutch independently of the retarding device, and means exclusive of said lost-motion device whereby the return of the clutch and armature to striking position returns the retarding device to initial retarding position.

5. In an electric-arc lamp, the combination of electrodes, one of which is movable, a clutch controlling the feed of said movable electrode, an electromagnet having an armature connected with said clutch, a dash-pot having amovable member, a pivotal weighted lever counterbalancing said movable member, a lost-motion device connecting said lever with the armature and clutch, and means exclusive of said device connecting said armature and clutch with the lever when the magnet loses its regulating-current.

In testimony whereof I have affixed my sig-,

nature in presence of two witnesses.

MELVILLE F. GOODRIOH.

WVitnesses:

R. M. PIERSON, A. O. RATIGAN. 

